Pravastatin (marketed as Pravachol or Selektine) is a member of the drug class of statins, used in combination with diet, exercise, and weight loss for lowering cholesterol and preventing cardiovascular disease. Pravastatin acts as a lipoprotein-lowering drug through two pathways. In the major pathway, pravastatin inhibits the function of hydroxymethylglutaryl-CoA (HMG-CoA) reductase. As a reversible competitive inhibitor, pravastatin sterically hinders the action of HMG-CoA reductase by occupying the active site of the enzyme. Taking place primarily in the liver, this enzyme is responsible for the conversion of HMG-CoA to mevalonate in the rate-limiting step of the biosynthetic pathway for cholesterol. Pravastatin also inhibits the synthesis of very-low-density lipoproteins, which are the precursor to low-density lipoproteins (LDL). These reductions increase the number of cellular LDL receptors, thus LDL uptake increases, removing it from the bloodstream. Pravastatin is primarily used for the treatment of dyslipidemia and the prevention of cardiovascular disease. It is recommended to be used only after other measures, such as diet, exercise, and weight reduction, have not improved cholesterol levels. The evidence for the use of pravastatin is generally weaker than for other statins. The antihypertensive and lipid-lowering treatment to prevent heart attack trial (ALLHAT), failed to demonstrate a difference in all-cause mortality or nonfatal myocardial infarction/fatal coronary heart disease rates between patients receiving pravastatin 40 mg daily (a common starting dose) and those receiving usual care. Pravastatin is generally well tolerated; adverse reactions have usually been mild and transient. In 4-month-long placebo-controlled trials, 1.7% of Pravastatin-treated patients and 1.2% of placebo-treated patients were discontinued from treatment because of adverse experiences attributed to study drug therapy; this difference was not statistically significant.